How do I install PEARL sensors for accurate people counting?
Best practices for mounting PEARL people counting sensors for accurate traffic measurement and reliable performance.
Table of Contents
Overview
You can improve PEARL counting accuracy by installing the sensors 24” or 54” high, keeping devices within 15 ft of each other, and ensuring both units are properly aligned with no obstructions between them
PEARL Installation Requirements
Mounting Height
54" high → to count adults only (ideally at shoulder height)
24" high → to count adults and children.
Distance Between Devices
- Install PEARL devices no more than 15 ft apart
- For entrances exposed to direct sunlight, install devices no more than 7 ft apart
- Shorter distances improve counting reliability
Alignment
- Align both PEARL devices so the “eyes” at the bottom face each other directly
- Ensure there are no obstructions between devices, including:
- Door handles
- Signage
- Fixtures
- Window frames
Any object blocking the beam can cause inaccurate counts.
Learn more about PEARL blockage here: Pearl Sensors Blocked
Which Side Should the Main and Secondary Units Be Installed On?
For correct direction detection:
- Install the Main unit on the LEFT side of the entrance
- Install the Secondary unit on the RIGHT side
- Always determine left and right while standing inside the store looking outward
Installing the units on the wrong sides may cause inaccurate entry and exit reporting.
What Height Should PEARL Sensors Be Installed At?
PEARL mounting height determines what traffic is counted.
To Count Adults Only
- Install devices approximately 4 ft high
To Count Children
- Install devices approximately 2 ft high
Can PEARL Sensors Be Installed on Inward-Opening Doors?
No. PEARL sensors should not be installed on inward-opening doors because the door itself can block the infrared beam, creating missed or false counts.
NOTE: If installing PEARL at an entrance with inward-opening doors, mount the devices beyond the door swing path, further inside the location, so the door does not block the infrared beam and cause inaccurate counts.
Outward-opening doors: Yes, PEARL works with doors opening outwards
How Should PEARL Devices Be Mounted?
Always mount PEARL devices using the mounting bracket.
- The bracket is designed to support and align the device properly
- The safety screw is only intended to secure the device after mounting
- Do not mount the device using the safety screw alone.
Incorrect mounting can cause:
- Misalignment
- Unstable positioning
- Inaccurate counting
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Can Wide Entrances Cause Missed Counts?
Yes.
At wider entrances, especially near the 15 ft maximum distance, PEARL sensors have a higher risk of missed counts.
This occurs when:
- Multiple people walk through simultaneously
- One person breaks the beam while others walk alongside them
- People cross the Main and Secondary units at the same time
Because one person already breaks the beam, additional people walking beside them may not be counted separately.
More info here: Blockage Article
I have mounted my PEARLs, what should I do next?
- You can then proceed with the Wi-Fi configuration in the Storetraffic App.
Start counting with PEARL - Perform a walk test, to ensure that the PEARL is counting correctly.
PEARL Walk Tests
✅ Following these installation best practices will ensure your PEARL sensors deliver accurate and reliable traffic counting data.
FAQ
Q : Why are my PEARL sensors not counting accurately?
Common causes include:
- Devices installed too far apart
- Misaligned sensors
- Obstructions blocking the beam
- Incorrect Main/Secondary positioning
- Devices mounted on inward-opening doors
Q : What is the ideal installation distance for PEARL devices?
For best performance:
- Standard entrances: up to 15 ft apart
- Direct sunlight exposure: up to 7 ft apart
Q : Can sunlight affect PEARL accuracy?
Yes.
Direct sunlight can interfere with the infrared beam. Reduce the distance between devices to 7 ft in areas with strong sunlight exposure.
Q : What happens if the PEARL devices are not aligned properly?
If the devices are not directly facing each other, the beam may not function correctly, resulting in missed or inconsistent counts.
Q : Can one PEARL pair cover a very wide entrance?
Wide entrances increase the likelihood of simultaneous crossings and missed counts. SMS recommends a 3D Scope II camera for wide entrances because it can track multiple people crossing simultaneously across a larger coverage area with greater counting accuracy.